This phase I clinical trial is part of a multi-project program to develop a peptide-based immunotherapeutic for HIV infection. The underlying strategy of this approach is to control and/or eradicate chronic retroviral infection through the induction of virus-specific cytolytic T lymphocytes (CTL) targeted at highly conserved regions of HIV-1. In this trial, up to 12 persons with asymptomatic HIV infection and CD4 cell counts > 500 cells/mm3 will be randomized to receive one of two formulations of a peptide therapeutic or matching placebo. Participants will meet certain entry criteria, including HLA 2. 1 positivity and negative serologies for HBV infection. Treatment assignment will be random, and the study will be double-blinded and placebo controlled. Participants will receive 4 injections, 4 weeks apart. Data will be gathered concerning safety and tolerability of the immunotherapeutic, as well as preliminary data on its effect on measurements of viral load and immune function. Both men and women, 18 years of age and older, will be recruited. Special efforts will be made to enroll women and persons of color. The study will be conducted at the Massachusetts General Hospital by a highly experienced group of investigators. There are potential liabilities for patients participating in this trial, which include the possibility of physical, psychological, legal and social harm. Special steps will be taken to minimize these risks. Patients will be enrolled only after full informed consent is obtained and the protocol approved by the Massachusetts General Hospital institutional Review Board.